Digikey PB boards

The work is part of the proto process. My current project have 3 boards.

1. 25x27
2. 50x27
3. 100x60

The complex routings are only in the center 50x27 area, and they are filled with chips also. It might work if i can put chips inside a 6 layers PCB.

Pinout for board #2, which would give me 30 ports up and 20 ports down.

//______XL___LW___L_____R____RW___XR___ //_1_____________VB___3v3______________ //_2____________C13___Gnd______________ //_3____________C14____5v______________ //_4____________C15____B9______________ //_5____VB__TBD___R____B8___TBD__3v3___ //_6___TBD__TBD__A0____B7___TBD__TBD___ //_7___TBD__TBD__A1____B6___TBD__TBD___ //_8___TBD___A2______________B5__TBD___ //_9___TBD___A3______________B4__TBD___ //_A___TBD___A4______________B3__TBD___ //_B___TBD___A5_____________A15__TBD___ //_C___TBD___A6_____________A12__TBD___ //_D___TBD___A7_____________A11__TBD___ //_E___TBD__TBD__B0___A10___TBD__TBD___ //_F___TBD__TBD__B1____A9___TBD__TBD___ //_G____5v__TBD__B2____A8___TBD__Gnd___ //_H____________B10___B15______________ //_I____________3v3___B14______________ //_J____________Gnd___B13______________ //_K_____________5v___B12______________

And labor intensive.

Do you need to? Besides, once you solder all those vias the inner traces are inaccessable and invisible.

My 4-layer boards are usually traces, ground, power pours, traces. The inner layers aren't very interesting.

e> traces are inaccessable and invisible.

The top and middle boards are soldered together, via the wings. The combined board plugs into a ZIP40 socket, no soldering.

Mines are all traces. I don't have ground planes.

The black pill (STM32F411, QFN48) has around 20 usable ports on a DIP40. I have around 10 common pins so far. It might be too difficult to make it totally pin compatible without using too many vias, or too big the board.

I am trying to fit a TQFP100 on a DIP40. The chip overlaps the middle pins, so i don't have pins there.

COTS board is easy to get started, but just as easy to run into limitations.

The stackup change makes the strays hideously different though.

Cheers

Phil Hobbs

Yes, give up making it compatible. I will have to go with a 4 boards solution.

1. Shuttle board on XL & XR (eXtreme Left and Right).
2. WingDip STM32F469/411 in QFP100.
3. Shape shifter to bring middle 6 pins of LW and RW (Left and Right Wing) back to the center.
4. Base board with 40 pins ZIF.

The $20 469 (1M flash) is easier to order than the $10 411.

______XL___LW___L_____R____RW___XR____|_______B/B____ _1_____________VB___3v3_______________|____B12____5v _2____________-*-___Gnd_______________|____B13___Gnd _3____________-*-____5v_______________|____B14___3v3 _4____________-*-____B9_______________|____B15___B10 _5____VB__-*-_-*-____B8___-*-__3v3____|_____A8____B2 _6___-*-__-*-_-*-____B7___-*-__-*-____|_____A9____B1 _7___-*-__-*-__A1____A6___-*-__-*-____|____A10____B0 _8___-*-___E3______________B5__-*-____|____A11____A7 _9____E4__C13_____________A10__-*-____|____A12____A6